Sensors having the function of rate-of-revolutions sensors are explained, for example, in the series of publications by Messrs. Robert Bosch GmbH, "PKW-Bremsanlagen mit ABS" (Passenger Car Brake Units with Anti-lock System), first edition of September 1989, page 20. These rate-of-revolution sensors operate by the induction principle. The housing is either fabricated from a stainless steel casing or of plastics material, a chisel pole or a rhombic pole as the assembly position of the sensor may be and projecting from the housing being directed to an impulse wheel fixed to the wheel hub. The pole stud is furnished with a permanent magnet within the housing which as an essential component of the measuring element generates a magnetic field and of the induction of a voltage within the coil winding positioned on the pole stud as soon as there is a rotation of the impulse wheel.
The rate-of-revolutions sensors described above have, however, the disadvantage that special provisions are required in order to ensure a smooth functioning which must, among others, protect the sensor against mud and moisture. This includes the greasing of the sensor and the exact adjustment of the gap between the impulse wheel and the sensor. In addition, the relatively insufficient miniaturization and the comparatively heavy weight of the prior-art sensors contrasts with the requirement of an optimum integratability.
It is, therefore, the object of the invention to create a sensor of the kind mentioned above which is distinguished by a particular suitability for miniaturization, by a great versatility and integratability and which, without being sensitive to mud and splash water, ensures a signal processing at any time, without particular adjusting procedures and corrosion protecting measures being required.
According to the invention, this object is achieved by a process for the manufacture of such a sensor.
The embodiments of the invention are enunciated which will be illustrated and explained in more detail in the following in conjunction with the further features and advantages of the invention, making reference to several accompanying drawings (FIGS. 1 to 3).